1. Field of The Invention
This invention relates to a furnace for melting metal and more particularly to an improved reverberatory furnace for melting aluminum scrap and a process for use therewith.
2. Description of the Prior Art
In the refining of metals, a fuel fired furnace is supplied with the solid metal to be melted. It is economically desirable to charge the furnace with scrap metal in order to recover the metal from the scrap materials. However, the use of metal scrap has certain drawbacks in that the scrap is normally contaminated with combustibles, particularly hydrocarbons, such as oil, paint, grease and the like, and the contaminating material will be volatilized when the metal is heated and will pass off from the metal as an undesirable atmospheric pollutant.
It is important that any system devised to deal with the volatile emissions should avoid, as much as possible, oxidation of the metal, which would decrease recovery. Metal lost to oxidation contributes significantly to the cost in converting the solid metal to molten metal. The approach disclosed in U.S. Pat. No. 3,933,343 provides a well-type melting furnace divided into two communicating wells: a receiving well for the scrap material and a main holding well for the molten metal. A vaporization chamber over the scrap receiving well collects combustible fumes from the scrap and preheated air for ignition at a burner in the combustion chamber over the main holding well. A large supply of air is provided to the melting furnace through an opening(s) at the top of the vaporization chamber. Special control means are required in the melting furnace of U.S. Pat. No. 3,933,343 to compensate for the excessive amounts of air which might otherwise develop therein, and to maintain the proper fuel-air ratio for complete combustion of the scrap fumes and burner gases. It would be highly desirable if an improved method of melting scrap metal could be found which utilizes a melting furnace having a simple and efficient design and requiring no complex provisions for combustion control, and which does not utilize excess air for combustion, thereby minimizing oxidation of the scrap metal.